Process design and comprehensive comparison of coal- and biomass-fired oxy-combustion power plant

Oxy-combustion is a promising option to achieve large-scale CO₂ emission reduction associated with coal-fired power plants. However, its commercial application is greatly restricted due to the large efficiency penalty and high cost of electricity. In this paper, a novel 1000 MW single reheat oxy-combustion power plant is proposed by adopting the heat capacity flowrate matching method to reduce irreversible loss and increase heat recovery of the overall power plant. A quantitative comparison of novel coal- and biomass-fired cases is conducted. The results show that the net electric efficiency of the novel oxy-combustion power plant improves by 0.85% points with a 1.0% points enhancement in the exergy efficiency and a 1.1 $/(MW·h) reduction in the cost of electricity compared with the reference case. When biomass is selected as the fuel, the net electric efficiency of the novel system increases by 1.1% points, and 4.0 MtCO₂ is removed from the atmosphere annually. Exergy analysis reveals the energy-saving mechanism of the novel system. Economic analysis indicates that total investment can be recovered within 1.8 years. This work provides an efficient and economic scheme for the design of oxy-combustion power plants.